This invention relates to concrete panels, and particularly to such panels as may be used for constructing the walls of concrete buildings, especially the exterior walls of such buildings, where it is desirable that thermal insulation be provided by such exterior walls so that a loss of heat from the interior of the building to the exterior thereof is minimized. In another aspect of the invention, the concrete wall panels are constructed to provide sound absorption so as to insulate the interior of the building from bothersome and even destructive noises outside a building, or which may be used in a fence line for instance such as the type that surround housing developments to shield such developments from the noise pollution created by adjacent street and highway traffic. Accordingly, it is one of the objects of the present invention to provide a precast concrete panel that may be manufactured at a point remote from the point of installation and then transported to such point of installation and be hoisted into its final position.
The construction of concrete buildings through the expedient of precasting concrete panels which are then transported to the building site and hoisted into position, even for multistory buildings, is a relatively recent innovation. Heretofore, concrete buildings have been cast in place by pouring concrete into forms constructed to contain the concrete until it sets, after which, the forms are removed. With the increse in labor and material costs, such construction methods have become prohibitive in cost and other innovations have had to be developed to reduce costs. Such innovations in most instances involve the pre-casting of concrete panels and the subsequent transportation of such panels and the hoisting thereof into ultimate position.
With the increased emphasis on the necessity to conserve energy, another problem that has arisen is the escape of heat from the interior of a building to the exterior thereof, thus constituting a waste. Accordingly, another innovation that has occurred is the insulation of concrete panels to minimize or prevent the passage of thermal energy therethrough. Accordingly, another object of the present invention is to provide a concrete building panel incorporating such thermal insulating means.
In addition to the conservation of heat energy, it has been found that productivity of personnel working within a concrete building can be increased if noise level within the building or within the immediate area is maintained within certain limits. Accordingly, another object of the present invention is to provide a pre-cast concrete panel incorporating sound absorbing means therein.
As indicated above, one of the motivating factors for innovations of this type in the construction industry has been the tremendous increase in the cost of labor and materials. Thus, another object of the invention is the provision of a concrete building panel designed in a way to save time in its manufacture and which may be assembled with other such panels in an efficient way to save the cost of field labor and energy.
In most instances, poured in place concrete buildings are considerably heavier than buildings fabricated from pre-cast panels. Such poured in place concrete buildings require much heavier and therefore most costly footings to support the weight of the building, and as indicated above, utilize building procedures that are inherently more costly. Accordingly, still another object of the invention is the provision of a light weight pre-cast concrete building panel which weighs much less than a conventional concrete panel, thus resulting in a significant saving of materials, but also substantially reducing vertical design loads and lateral earthquake induced loads.
As indicated above, one of the problems sought to be solved by the pre-cast concrete panel of this invention is the saving of thermal energy. Accordingly, one of the objects of the present invention is the provision of a pre-cast concrete panel in which the heat loss through the panel can be a sixth to a fiftieth of that through conventional concrete panels of equal thickness.